1. Field of the Invention
The disclosed subject matter is in the field of urban landscaping, particularly tree wells and tree grates.
2. Background of the Invention
Urban landscape design often includes trees. Trees are typically planted near urban sidewalks. Well-placed trees are a pleasant contrast to large urban skyscrapers and congested streets. Trees are aesthetically pleasing and give people in urban environments a bit of nature. While trees are desirable in an urban environment, integrating trees into an urban setting has many challenges.
One challenge to planting trees in an urban environment is maintaining the health of the trees. A tree in an urban environment faces many hazards not seen in the natural environment, such as pollution, people who may damage trees, bicycles chained around a tree, and dogs that treat urban trees like a restroom. In addition, the soil in an urban environment can lack the nutrients a tree needs and sometimes it can be challenging for an urban tree to get water.
There are three main ways that landscapers and urban planners have attempted to integrate trees into urban environments, tree boxes, tree grates, and paving around the trees. While each of these methods allow for the integration of trees into an urban environment, each method has major drawbacks.
One method of integrating a tree into an urban environment is to place the tree inside of a tree box. The tree is planted inside of a small boxed area and soil surrounds the tree instead of concrete. However, in an urban setting people will step on the soil, compacting it. When the soil is compacted, the tree will not be able to get enough air and water and compacted soil can cause storm water problems. The roots of a tree store water, meaning that puddles will collect around the tree on rainy day. Tree boxes can also attract weeds. If weeds are growing in a tree box, that means that a landscapers must constantly maintain the tree box or else the health of a tree may be compromised.
Surrounding an urban tree with a tree grate will solve many of the problems associated with a tree box. A tree grate is typically metal and has openings that allow water and nutrients to get to the tree. A tree grate can feature an interesting aesthetic design. Tree grates will solve the drainage and weed problems created from a tree box, but present new issues. Trash can get stuck underneath the grate potentially attracting rodents. Grates can become odorous in areas where there are many dog owners. Often times, a grate cannot withstand the tree growth and will buckle. If the grate is constructed of a strong, sturdy material, there is a chance that the grate may stunt the growth of a tree or damage the tree. Grates are not one size fits all, and problems can arise when a tree is too small for a grate. If the opening is too big then, adding a tree grate does not solve the problems associated with a tree well, such as weeds and drainage issues. Furthermore, because tree grates contain openings to allow for water to get to the tree, it must comply with the Americans with Disabilities Act (ADA). The openings of tree grates can cause hazards for people using a cane or a walker, and in some cities the ADA has raised objections to the use of any tree grate, even ones complying with the ADA.
The least popular method for integrating trees into an urban environment is paving over the tree. Paving over the tree causes the tree roots to push up. When the tree roots push up through the ground, it can cause the pavement to buckle making it uneven. The uneven pavement can create a dangerous condition, especially to people with disabilities.
There have been some attempts at integrating trees into an urban environment. U.S. Pat. No. 3,571,972 to Carter discloses a collar that fits around a tree. The collar is round and contains slits and will prevent weeds from growing near the tree. WO 2006099851 to Baumscheibe discloses a tree grate. The tree grate is flush with the ground and made from a material consisting of mineral aggregates and organic adhesives. While these inventions are useful to integrating a tree into an urban environment, they do not solve the problems associated with tree grates, such as trash and rodents.
Some of the attempts to integrate trees into an urban environment involve the development of a flexible concrete that be poured over the tree that a lows for water to reach the tree roots, but not buckle due to tree roots. U.S. Pat. No. 3,891,585 to McDonald discloses an elastic pavement repair composition. The composition disclosed in McDonald is not specifically tailored for use with trees. U.S. Pat. App. 2011/0064517 to Sader, and all disclose a pervious concrete and lists tree wells as one of many possible uses for the concrete. U.S. Pat. App. 2004/0200140 to Alexander describes a tree skirt made of a flexible rubberized material. Alexander's invention can be adapted for use with tree grates or the skirt can be used without a tree grate. While Alexander's invention solves some of the problems involved with tree wells, it does not solve all of them, such as odors emerging from tree wells.